The abandoned bridge is the sole hint here of a lengthy environmental battle that may be nearing its end. For more than a decade, activists have fought a state-owned hydropower company’s plans to build giant dams on the Nu, the last natural river in China. Now, dam opponents say they scent victory.

They cite several reasons: China’s slowing economic growth is flattening demand for electricity. Authorities are spooked by geologists’ warnings of earthquake risks near proposed sites. And in what may be a change of heart, China’s top leaders are sending new signals of respect for the environment.

“It is clear this government has more environmental caution” than its predecessors, says Ma Jun, a veteran ecology warrior in Beijing, citing recent heightened efforts to curb air pollution and carbon emissions. “It is paying more attention to environmental protection.”

That might just be enough to save the Nu, China’s only undammed river, which flows through a UNESCO-designated World Heritage site in the province of Yunnan.

The United Nations body describes the region as “the area of richest biodiversity in China and maybe the most biologically diverse temperate region on earth,” home to animals such as the rare red panda and birds like the white-speckled laughingthrush.

Neither the government nor the prospective dam builder, the electricity giant Huadian, has yet published any environmental impact assessment, as they are obliged to by law.

But if the project goes ahead, “it will destroy the river ecology,” argues Yu Xiaogang, head of Green Watershed, an activist group that opposes the dam and is based in Kunming, the provincial capital of Yunnan.

“It will not be good for us,” agrees Xiong Xiangnan, a young farmer sitting by the side of the road hoping to sell visitors a plump trout that he netted overnight. “Dams will pollute the river and hurt the fish.”

Building reservoirs behind the dams, he adds, means that “we will lose our farmland and our terraces,” which are a source of sustenance for many local people.

A coveted energy resource

The Nu River carves its way through some of China’s most stunning scenery, boasting towering gorges, snowcapped mountains, and alpine meadows as the river runs downstream toward tropical Myanmar (Burma), where it is known as the Salween, and from there into the Andaman Sea.

Hydropower companies have long coveted the river’s energy potential. But in 2004, amid pressures that included public protest, the government shelved initial plans for a cascade of 13 dams down the Nu. In 2013, however, Beijing quietly allowed Huadian to proceed with planning for five dams, including the Songta dam in Tibet.

Since then, the National Development and Reform Commission (NDRC), China’s top planning agency, has sat on a pre-feasibility study for the Songta dam. Its intentions remain unclear.

In recent weeks the provincial Communist Party boss of Yunnan, Li Jiheng, has given new hope to environmental activists, declaring a ban on small hydro projects on the Nu’s tributaries and announcing his administration’s intention to designate the river gorge as a national park – a move that would make tourism, not hydropower, an economic driver.

“The Nu River will become a world-level tourism destination in five to 10 years,” China National Radio quoted Mr. Li as saying last month. “It will succeed, even surpass the Grand Canyon.”

“This is a good sign,” says Stephanie Jensen-Cormier, China director for International Rivers, a pressure group advocating social and environmental responsibility in dam construction. “It makes the government more likely to stop the big hydro projects,” she adds, though she stresses that no decision appears to have been made. That decision ultimately lies with the NDRC and the cabinet in Beijing, and officials there have been tight-lipped.

Still, Li’s new approach cheers one local resident who makes his living from mountain guiding; he asked to remain anonymous because the dam issue is still politically sensitive. “If you are making a national park, you can’t have dams,” he says. “How could you develop tourism with big dams?”

An impact far away

If the dams were to be canceled, that would be good news, too, for farmers a thousand miles away, who make their living in Myanmar and Thailand on the banks of the Salween.

The Chinese government has refused to sign a 1997 UN water-sharing convention, and has built and operated dams without regard for downstream neighbors. But early in March, for the first time, Beijing announced in advance that it would be releasing water from the Jinghong dam on the Mekong River.

The rising water level still washed out crops and disrupted fisheries in Laos and Thailand. But the announcement suggests greater openness in Beijing. Late last year, it joined the five other nations through which the Mekong flows in launching a “cooperation mechanism” that might at least give downstream farmers some warning when the river level is going to rise suddenly.

China, which has built more than half of the world’s 80,000 dams, is planning to boost hydropower’s share of electricity production over the next 10 years to reduce carbon emissions, in line with its pledges at the recent climate summit in Paris. But with predicted demand for electricity falling, the need for new dams is likely to ease, energy analysts say.

Beyond that, critics say, giant dams are not as “green” as their builders claim, once their environmental and social impact is taken into account. Some 17,000 indigenous ethnic minorities would be displaced by the dams and reservoirs planned in Yunnan, according to official figures.

None of them have been consulted about their future. “I’m not sure it will happen,” says Hu Xiaying of the dam project, as he takes a break from selling the cinder blocks he manufactures from gray river sand and cement. “My neighbors have told me it won’t, but I haven’t heard anything official.”

Nobody anywhere has heard anything official, although the law is supposed to guarantee public consultation. Officials at all levels either refuse to comment or restrict themselves to saying that the project has not yet been approved.

A changing political landscape

But the Chinese political landscape is changing in ways that are shaping a new and less benevolent landscape for hydropower companies.

The growth in demand for electricity is cooling with the economy, and the government’s longer-term plans to shift away from an industrial base toward a more service-oriented economy will also exert downward pressure; industry consumes 80 percent of China’s electricity output.

“There is oversupply in the Chinese power market, so power-generating companies are not very excited about the prospect of investing more money,” says Zhang Boting, deputy head of the China Society for Hydropower Engineering and a strong dam booster.

“Pressure from the market is now stronger than NGO pressure,” he adds. “It is possible that the market will kill” the Nu dams project.

The economic outlook for the project is further dimmed by the need to build expensive transmission lines connecting the prospective dams to the grid, and by the fact that experts say that it would be profitable only if all five dams are built, making maximum use of the water.

Whether that would be safe is in doubt, however, in light of geological reports by independent retired experts warning of a serious earthquake risk in the Nu Valley. Former Premier Wen Jiabao, a geologist by training, weighed that threat in his decision to suspend the project. Politically, to abandon Mr. Wen’s caution could carry huge risks for his successor, Li Keqiang, should there be a quake.

At the same time, President Xi Jinping’s anti-corruption campaign is undermining the political clout that hydropower industrial giants have long enjoyed. Liu Tienan – China’s former energy czar – is now behind bars for taking bribes. In Yunnan itself former provincial Communist Party Secretary Bai Enpei, a vociferous supporter of damming the Nu, is also now in prison.

Changing central government approaches to poverty reduction is also having an effect. Traditionally, local government leaders were judged solely by their ability to boost growth of gross domestic product; that policy encouraged them to invest in quick-return schemes such as roads and malls that did not necessarily improve the local quality of life.

For the past two years, the poorest counties in China have been exempted from the old gross domestic product test, inducing them to try more targeted policies to improve the standard of living.

The Nu Valley is among the poorest places in China, points out Mr. Yu of Green Watershed, “and if GDP is no longer so important to local leaders, then hydro companies lose some of their bargaining power.”

Yu is most encouraged, though, by what he sees as a change in tone in the government’s slogans about the environment.

Once, he said, the official line was “change green mountains and blue water into gold mountains.”

Under President Xi, that slogan has changed to “green mountains are gold mountains,” signifying that protecting them can also promote economic growth.

Fellow environmental activist Mr. Ma also sees the shoots of a greener mind-set at the highest levels in Beijing.

It was “very impressive,” he says, to hear Xi, on a recent visit to the Yangtze, telling local cadres that the river, fouled by decades of industrialization, was “an important ecological treasure.” He urged them to focus on “major protection instead of major development.”

Ma and other activists see Xi’s words as a broader directive on environmental issues.

The Chinese government’s decisionmaking process is secretive and complicated by myriad interest groups. The authorities may never formally announce a decision one way or the other on the Nu dams, choosing simply to continue to withhold approval and maintain politically useful ambiguity.

But, says Wang Yongchen, a former journalist who has devoted much of her life to protecting the Nu River, “each day of delay gives us a little more hope.”